A novel nanoscale MOSFET with modified buried layer for improving of AC performance and self-heating effect Morteza Rahimian, Ali A. Orouji n Electrical Engineering Department, Semnan University, Semnan, Iran article info Available online 15 March 2012 Keywords: Self-heating effects Silicon on insulator Capacitance 2D device simulation abstract In this paper, we propose a unique feature exhibited by novel nanoscale metal oxide semiconductor field effect transistors (MOSFETs) with an undoped buried region (UBR) under the channel and a buried oxide only under the source and drain region. The key idea in this work is suppression of the self-heating effect and gate–substrate capaci- tance improvement by modifying the buried layer. As a result, we demonstrate that the proposed structure called undoped buried region MOSFET (UBR-MOSFET) exhibits gate– substrate improvement in addition to excellent temperature performance when compared to conventional structures. Using two-dimensional and two-carrier device simulation, we have examined various design issues of the UBR-MOSFET and provided the reasons for the improved performance. The simulated results show that the novel structure is a suitable device for high temperature and electrical performances. & 2012 Elsevier Ltd. All rights reserved. 1. Introduction Silicon-on-insulator metal oxide semiconductor field effect transistors (SOI-MOSFETs) offer many benefits, such as low leakage current, latch up elimination, and reduction of parasitic capacitance in comparison with bulk MOSFETs [1, 2]. The buried insulating layer in the SOI-MOSFETs insulates the device electrically from the bulk of the semiconductor. But this thin film, typically silicon-dioxide (SiO 2 ) thermally insulates the SOI-MOSFETs from the bulk. The insulation is because of low thermal conductivity of the oxide that acts as a barrier for heat dissipation [3,4]. This much greater temperature rise at the SOI-MOSFETs than that in the bulk devices under similar conditions leads to carrier mobility decrement and corresponding drain current reduction. Therefore, self-heating effect (SHE) compensation becomes an important point for improving the circuit performance. Several attempts have been carried out to decrease high temperature such as buried dioxide replacement by another insulator that has higher thermal conductivity, reduction of the buried oxide thickness, and so on [5–14]. Unfortunately, reduction and elimination of the buried insulating layer, and silicon-dioxide replacement with another insulator with higher thermal conductivity introduce other disadvantages such as capacitance increment that reduces device speed [5–9]. The challenge that we have addressed in this paper, therefore, is to examine if we can improve the device capacitance while we reduce the temperature of the device, too. This could result in improved MOSFET performance. Based on the above idea, the aim of this paper is therefore to propose for the first time, a new device structure called the undoped buried region MOSFET (UBR-MOSFET) by introdu- cing a region that acts as an intrinsic region or a region without doping under the channel and a buried oxide only under the source and drain regions. The novel structure has been simulated using a two-dimensional device simulator [15] to examine drain current, temperature distribution due to SHE, and device capacitance. Furthermore the proposed structure was compared with a conventional SOI-MOSFET (SOI-MOSFET) and a MOSFET structure with a buried oxide only under the source and drain regions (BOSD regions) and without UBR region (BOSD-MOSFET). We demonstrate that Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/mssp Materials Science in Semiconductor Processing 1369-8001/$ - see front matter & 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.mssp.2012.02.016 n Corresponding author. Tel.: þ982313354100; fax: þ982313331623. E-mail address: aliaorouji@ieee.org (A.A. Orouji). Materials Science in Semiconductor Processing 15 (2012) 445–454